login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A152997 Twice 13-gonal numbers: a(n) = n*(11*n - 9). 2
0, 2, 26, 72, 140, 230, 342, 476, 632, 810, 1010, 1232, 1476, 1742, 2030, 2340, 2672, 3026, 3402, 3800, 4220, 4662, 5126, 5612, 6120, 6650, 7202, 7776, 8372, 8990, 9630, 10292, 10976, 11682, 12410, 13160, 13932, 14726, 15542 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..38.

Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

a(n) = 11*n^2 - 9*n = A051865(n)*2.

a(n) = a(n-1) + 22*n - 20 (with a(0)=0). - Vincenzo Librandi, Nov 27 2010

MATHEMATICA

s=0; lst={s}; Do[s+=n; AppendTo[lst, s], {n, 2, 6!, 22}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 02 2009 *)

PROG

(MAGMA) [ n*(11*n-9): n in [0..50] ];

(PARI) a(n)=n*(11*n-9) \\ Charles R Greathouse IV, Jun 17 2017

CROSSREFS

Cf. A051865 (13-gonal numbers).

Cf. numbers of the form n*(n*k - k + 4))/2 listed in A226488 (this sequence is the case k=22). - Bruno Berselli, Jun 10 2013

Sequence in context: A132861 A210848 A247957 * A229573 A067204 A202077

Adjacent sequences:  A152994 A152995 A152996 * A152998 A152999 A153000

KEYWORD

easy,nonn

AUTHOR

Omar E. Pol, Dec 22 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 25 15:34 EDT 2019. Contains 326324 sequences. (Running on oeis4.)